So let me preface this, this is not about saving money at the pump otherwise I would have not put an LS in a brick. This is purely about extending the range since I am planning some trips to some desolated areas. I am aware of larger fuel tanks, gearing, tire size, tuning, etc to obtain my goals, but I am currently working on the motor so my question is specifficly about the motor.

I am working on a new VVT L92 non DOD engine build to replace the 5.3 gen 3 motor in my Wrangler. My goal is to build this motor to be efficient at crusing RPMs around 1500rpm to 2500rpm and its needs to safey (but does not need to be the most optimal) run 87 octane out of the pump.

Are there cam shafts that would be more fuel efficient than the stock truck cam? Are there other options I can look at while building the motor? If I replaced the belt driven power steering pump with an electric pump, would it offset the extra load on the alternator?

Since this will be primarily lower rpms, I was thinking a stroker might even help with this allowing me to keep out of the throttle while at 2000 rpm fighting massive wind resistance. Any thoughts on this?

Thanks all for the help.

 

Larger displacement = more fuel used. Gotta feed the inches.
The only time P/S is any real drag is when you are steering.
The only cam that might save a little gas is the BTR Truck Torque cam. 202/202, .511/.511, 111 +1 LSA.
Slightly bigger than the stock L92 cam (198/209, .500/.500, 115 LSA) but the tighter LSA will kick up low end torque.
You will need to delete VVT to use this or almost any other aftermarket cam.

 

What kind of MPG are you getting now?

 

VVT when introduced in the 5.3s was good for a solid mile per gallon. Not sure about the 6.2s.

Curious, what kind of vehicle is this, a Jeep Wrangler? Those are tiny compared to my Yukon XL and Sierra.

The Sierra is lifted on 35s and gets 11 mpg on gasoline, would have gotten 18-19 on the highway if it were stock. Jerry cans are your friend!

 

I don't think there's much benefit to going into the motor with those guidelines. Basic bolt on's, fresh fluid changes for transmission, transfer case, differentials, power steering, brakes, cooling, fresh filters, new plugs, wires, belts & call it done etc when all maintenance is up to date.

Cold air
Exhaust
Electric fans
10% Under drive pulley
Crank scrapper
Colder thermostat
Dyno tune

Regarding strokers, mods & mpg as cubes go up mpg drops roughly in proportion unless something else changes. The slightly increase in efficiency from being square or over square with won't make up for the overall increase in fuel consumption that goes with the additional cubes.

Stock & basic bolt on's my LS1 99 T/A got 32.5 mpg highway. The 416 stroker lost over 11 mpg.

Details...

 

You will find your most efficient mod for fuel mileage is in the tune. My 434 powered Chevelle that’s 700+ at the flywheel gets over 20 mpg on the interstate in 6th gear. It’s all in the tune. I went from about 10.5 mpg to 21 mpg with tuning only. I don’t need or want performance at 1800-2000 rpm, where it cruises at.

 

I have a LS6/4L60E swap in my 98 Wrangler. 4:10 gears. At 65-70 mph it will knock down 17-18 mph. It is like driving a brick aero wise.
My 2020 Silverado has a 6.2/10 speed combo. At 65-70 mph it will knock down 21-22 mph.
My .02 is that you could stroke the 5.3 allowing you to keep your current ECM and wiring harness. Also re-gear for lower rpms on the highway with bigger cubes. Small cam. Good heads like AFR's. Maybe a tighter converter. And as said above a good chassis/road tune to dial everything in like trans shift points if you have an auto.

 

Yeah your best bet IMO is to either tune it yourself, or find someone who would immulate a "lean cruise" strategy. It wasn't offered in the US, but it was in other countries. It wasn't here because of what it does with pollution.
If you get your afrs setup in your no load section properly, it can make a significant difference.
If you have ever seen legitstreetcars on YouTube, Alex did it on a Vette.

 

Lean cruise makes less CO and more NOx. But you can easily do lean cruise by going open loop SD

 

The stock ls3 in my 2012 corvette gets 30mpg with an A6 trans. For what it’s worth.

 

Being that the corvette probably weighs less than the OP car and isnt shaped like a brick helps with that.

 

You do know people are going to ask why a 6.2 and Wrangler for fuel efficiency. Pretty much the worst of each. But, we want what we want.

Typically, maximizing fuel efficiency in an engine is about maximizing intake manifold vacuum at the usage RPM, and engine torque output with minimal throttle to do so. Hence the VVT system. VVT does not add total power to an engine, it instead shifts the torque curve to where the engine is being used. Lower for lower RPM, and high for higher. You can often notice that a VVT and non-VVT engine as released from an OE will have the same peak power ratings.

My opinion would be to keep the stock cam and VVT system. Keep DoD system operational if it has it (go with new DoD lifters on those cylinder though, use spec weight oil and keep it clean). Use a low restriction exhaust. Use an electric radiator fan only, not a mechanical one. The difference in electric vs hydraulic steering would be small. Neither has much draw until they are used. Run max tire pressure, use lower vehicle speeds, manual transmission, slow down the accessory drive, hot thermostat, use narrow tires, low vehicle height, low vehicle mass, gear it to run less then 2,000rpm at your cruise speed, etc..... 4.8L would get better mileage than a 6.2L if you have to have a V8, less reciprocating mass and less airflow to fuel.

 

Turbo 4.8L. OP should give that setup a thought.

 

this!!

 

The other thing to consider aero wise is don't hang a bunch of stuff on the front like winches and light bars or big heavy bumpers front and rear. Also no roof racks. Keep the lift at a minimum.

 

Oh, but then it wouldn't be a JEEP!

 

Comp has a 210/224 114+9 for GENIVs with VVT and w/o AFM.

Electric accessories typically have a small overall net improvement even though your trading off parasitic losses over alternator load; but further benefit comes from being able to modulate it to reduce load when it's not needed (in the case of power steering, reducing assist if you're going straight down the road). Since the overall improvement for electric PS is only 2-3% economy savings, I doubt it's worth it unless you also have the means to toggle it off when steering assist isn't required.

 

Thanks everyone for the tips on this, lots to consider. I guess some info might help add context. Its a 2000 Wrangler with a gen 3 5.3 from a 2000 truck using the Holley Terminator. Currently 32" tires and 3.05 gear (will be 3.73 when I swap in the 6.2 and a Dana 44 to replace the current Dana 35). No lift or armor since this will not be bouncing off rocks or mud holes, but the trip I am planning is 4000miles one way with the last 500 miles being dirt/gravel.

So yes I know a 6.2 might be overkill but it is what I have lying around with the matching 6L80E and PCM from an 07 Escalade that I parted out. The 6000lb brick this came from gets better fuel efficiency (13/21) than my 3000lb brick with a gen 3 5.3 running the Holley Terminator (which is a great system, but probably not the best for my application) where I only get 13.5mpg with no doors or top regardless of flooring it or driving conservatively, city or highway, which the 4.0 got 11mpg in the same configuration.

If the E38 PCMs have a tune-able PWM output that is based on speed, I might be able to setup a way with a PWM fan controller to have an electric power steering pump adjust the amount of power needed based on speed which does add some complexities and fail points. But if something were to fail, it would not be had to bypass and have it just run 100% all the time.

I am planning other things to go in addition to the motor like an extended range tank, some aero mods.

 

I wouldn't compare that Escalade MPGs to your Wrangler, the gearing, aero and tune was to support for more MPGs on the Escalade. The tires definitely don't help and going to 3.73s wont either. Biggest kill factor is Aero and Gearing IMO. Your Wrangler is not only a brick being thrown in the air, but you also have more drag because of clearance under it. An Air Dam up front will help. I think with the right tools, tuning and work to aero you can achieve a solid 18-20MPGs @ around 65MPH average, at 55MPH will net you more. Just my guesstimations with what i have worked with an seen. LS can be a very efficient engine and I am not sure if you can save multiple tune on the Holley like i can with Pro EFI, but i had an "Eco" mode tune per say and then a "Crowd Eater" tune on a mustang. A delta of 3-5 MPGs between the two tunes @ 75MPH average.

 

BB tuned 5.3 2011 Tahoe got 15.8 same Tahoe with 6.2 L92 retuned (is a must) gets 14.8